Repeat multibeam mapping of two slope-confined canyons on the northwest Australian margin provides new understanding of the processes that are active in shaping these environments. The Cape Range and Cloates Canyons initiate on the mid- to lower continental slope, but are connected to the shelf via small channels and gullies. These canyons were first mapped systematically with multibeam sonar in 2008 and were remapped in 2020 during a biodiversity survey that also collected high-resolution imagery and biological samples from a deep-water Remotely Operated Vehicle. Comparison of features between the two surveys indicates active sliding, minor headwall retreat and continued excavation of deep floor depressions, reflecting the action of high energy turbidity currents. Significantly, intact blades of displaced seagrass imaged throughout both canyons at depths up to 4200 m indicates that sediment sourced from the adjacent continental shelf is being channelled through these canyon systems. Sedimentation likely regulates benthic communities in these canyons, with imagery showing highest densities of sessile invertebrates in habitats protected from sedimentation (e.g. rock overhangs). Repeat mapping provides an understanding of the dynamics of these canyons and a context for assessing and monitoring the stability of the seabed habitats within a marine reserve. <b>Citation:</b> Alexandra L. Post, Rachel Przeslawski, Rachel Nanson, Justy Siwabessy, Deborah Smith, Lisa A. Kirkendale, Nerida G. Wilson, Modern dynamics, morphology and habitats of slope-confined canyons on the northwest Australian margin, <i>Marine Geology</i>, 2022, 106694, ISSN 0025-3227, https://doi.org/10.1016/j.margeo.2021.106694.

The East Antarctic slope on the Sabrina margin has been shaped by diverse processes related to repeated glaciation. Differences in slope along this margin have driven variations in sedimentation that explain the gully morphology. Areas of lower slope angles have led to rapid sediment deposition during glacial expansion to the shelf edge, and subsequent sediment failure. Gullies in these areas are typically extremely U-shaped, initiate well below the shelf break, are relatively straight and long, and have low incision depths. Areas of higher slope angles enhance the flow of erosive turbidity currents during glaciations associated with the release of sediment-laden basal meltwaters. The meltwater flows create gullies that typically initiate at or near the shelf break, are V-shaped in profiles, have high sinuosity, deep incision depths and a relatively short down slope extent. The short down slope extent reflects a reduced sediment load associated with increased seawater entrainment as the slope becomes more concave in profile. These differences in gully morphology have important habitat implications, associated with differences in the structure and beta-diversity of the seafloor communities. This upper slope region also supports seafloor communities that are distinct from those on the adjacent shelf, highlighting the uniqueness of this environment for biodiversity. <b>Citation:</b> A.L. Post, P.E. O'Brien, S. Edwards, A.G. Carroll, K. Malakoff, L.K. Armand, Upper slope processes and seafloor ecosystems on the Sabrina continental slope, East Antarctica, <i>Marine Geology</i>, Volume 422, 2020, 106091, ISSN 0025-3227, https://doi.org/10.1016/j.margeo.2019.106091.